646' BOWMAN— ECOLOGY AND 



made by such methods as suggested by Abderhalden/^^ Euler/^* 

 and more particularly Thatcher/^^ who endeavored to isolate the 

 enzyme, tannase, from several varieties of apples. 



Methods. 



The fresh green hypocotyls were cut up and weighed in ten- 

 gram portions, i. e., ten grams from each hypocotyl. These por- 

 tions were then ground to a consistency of coarse saw dust by 

 pounding in a mortar with a little distilled water. Each portion was 

 then digested with 50 c.c. distilled water in a beaker on a water 

 bath at 40° C. for a half hour and the extract pressed out. The 

 semi-dry mass that remained was then further digested with 50 c.c. 

 of distilled water, the extract pressed out and added to the first 

 extract. This extract of 10 Gm. of hypocotyl was then filtered and 

 divided into two equal portions and each one made up to 100 c.c. by 

 the addition of distilled water. One flask of the filtrate was boiled 

 several minutes, then to each flask of filtrate a tenth gram of 

 Merck's standard tannic acid was added and both placed in an incu- 

 bator at 40° C. for twenty-four hours. After allowing this interval 

 for the enzyme to effect a change in the tannin content in the un- 

 boiled flasks, both the control flasks and the unboiled ones were 

 treated with four drops of concentrated ferric chloride to cause 

 precipitation of the tannin and the characteristic change in color. 

 In some of the tests the precipitate, bluish black in color, was fil- 

 tered off and then carefully washed, desiccated and weighed, but in 

 all these tests there was not any evidence to indicate the presence 

 of the enzyme tannase in the hypocotyl of these plants. The color 

 reactions for the boiled was just as dense as those for the unboiled 

 portions, while the weight of the desiccated precipitates likewise 

 showed no appreciable difference, so the absence of the enzyme is 

 apparently substantiated. 



Simultaneously with the performing of the above experiments 

 a complementary series of investigations was made to show the 



133 Abderhaklen, E., " Handbuch der Biochemisclien Arbeitsmethoden," 

 Berlin, 1910. 



121 Eulcr, Hans, " Allgemeine Chcmie der Enzyme," Wiesbaden, 1910. 

 135 Thatcher, R. W., " Enzymes of Apples," Jour. Ayri. Research, 1910. 



